Jacinda Ardern and the Winston Peters dilemma: Do nothing or take the nuclear option

Not for the first time, NZ First has scuppered government plans - and the party's leader keeps proving he has all the leverage.

Well, it happened again.

Back in June the justice minister, Andrew Little, announced plans to repeal the Three Strikes legislation, only to have Winston Peters publically humiliate him by pulling support for the bill at the last minute, informing his coalition partners of this via the media.

The past few months have seen an intensification of this same trick, with Peters pulling support for Labour's campaign promise to increase the number of refugees and the Employment Relations Amendment Bill, one of Labour's flagship policies.

And yesterday Peters pulled support for the government's new Crown-Māori Relations Agency, again at the last minute, again in a manner calculated to humiliate a senior member of Cabinet - this time deputy Labour leader Kelvin Davis.

It's incredibly destabilising for the government - and Peters is deputy prime minister of the government! - and the timing couldn't be worse for Jacinda Ardern, who is already the subject of a not-so-subtly-gendered debate about whether she's too "weak" to be prime minister. What on earth is going on?

It wasn't supposed to be like this. Peters has been a source of instability and chaos in every government of which he's been a member, but when this one was formed there was a genuine belief among his coalition partners that things would be different.

"He's learned from the mistakes of the past," new ministers assured themselves. "Besides, as foreign minister he'll be overseas most of the time!"

And then there was the tripartite nature of the Labour-New Zealand First-Green government. "A pure MMP government," as Ardern puts it. Because the votes of all three parties are required for passage through the house, the theory went, good faith and constructive relationships are baked into the nature of the arrangement. If you blocked your partners' bills then you wouldn't be able to progress your own legislative agenda.

And there's the problem: New Zealand First doesn't really have a legislative agenda. Its substantive wins are either front-loaded, in the form of ministerial portfolios, or delivered via the budget process, which all three parties have to support. And most of the items in the New Zealand First coalition agreement are things Labour and the Greens want to do anyway, so if they block them they'll be blocking their own policy agenda.

Labour currently has 67 bills in progress through parliament; New Zealand First has eight. This asymmetry gives Peters enormous leverage over Labour, and he's using it to implement a novel - for New Zealand - opposition-in-government strategy in which he appeals to soft National voters by routinely obstructing and embarrassing Labour and its ministers.

Peters' other point of leverage is his famous volatility. There's no relationship Ardern or anyone in her party can build with the New Zealand First leader that establishes goodwill, or ensures that any assurances or commitments he gives them have any validity or meaning - Peters just doesn't work that way.

But she can easily upset him, by publicly rebuking him, or pulling support for, say, the Waka-Jumping Bill, and this will damage his ego and earn his undying enmity and very possibly see him collapse her government in a fit of rage. Her ability to retaliate is incredibly limited. There are nuclear options or nothing.

This is a horrible position for Ardern and the rest of her Cabinet. There's this notion out there that the prime minister has to be "tough", and that this will solve her problems, somehow, but it's hard to be tough when you have no leverage and no agency.

Helen Clark is currently touring the country congratulating herself on her own toughness in power, but she too was equally helpless to control Peters when he was her coalition partner and foreign minister. Clark spent her last year in power feebly defending him in the teeth of an ever deepening corruption scandal, destroying any shreds of the possibility of her government winning re-election in the process.

Maybe Labour will figure out a way to control Peters. There are some smart people in the Beehive. But Peters' previous governing partners have all concluded that he's a problem without a solution, and the only viable approach is to indulge him while attempting to progress their policy agenda, trying to accomplish as much as possible before he tears everything down around them. That seems to be where Ardern finds herself now.